#include <iostream>
#include <cstring>
#define MAX 50+3

using namespace std;

typedef char Elem_Type;
typedef struct BiTree{
	Elem_Type data;//数据
    struct BiTree *Lchild;//左孩子
	struct BiTree *Rchild;//右孩子
}BiTree;      //要查找的元素  查找的地方    数组的长度
int Search_Num(Elem_Type num, Elem_Type *array, int len){
	for (int i = 0; i<len; i++)
		if (array[i] == num)
			return i;
	//return -1;//没有找到
 
}
BiTree *Resume_BiTree(Elem_Type *front, Elem_Type *center, int len){
	if (len <= 0)
		return NULL;
	BiTree *temp = new BiTree;
	temp->data = *front;
	int index = Search_Num(*front, center, len);
	temp->Lchild = Resume_BiTree(front + 1, center, index);
	temp->Rchild = Resume_BiTree(front + index + 1, center + index + 1, len - index - 1);
	return temp;
}
void PostOrderTraverse(BiTree *root){
	if (root != NULL){
		PostOrderTraverse(root->Lchild);
		PostOrderTraverse(root->Rchild);
		cout << root->data;
	}
}
 
int main(void){
	Elem_Type *preorder = new Elem_Type[MAX];//前序
	Elem_Type *inorder = new Elem_Type[MAX];//中序
	cin >> preorder;cin >> inorder;
	BiTree *root = Resume_BiTree(preorder, inorder, strlen(inorder));
	PostOrderTraverse(root);
	cout << endl;
	return 0;
}